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Possible blood biomarkers for poorer asthma control identified

Research Activities October 2011, No. 374

Blood levels of certain small proteins, including both cytokines and serum growth factors, may help physicians identify patients with chronic asthma who have well-controlled asthma and better quality of life, according to a new study. A variety of cytokines (such as interleukins, tumor necrosis factors, and interferons) are known to be involved in immune system regulation. About 7 percent of adults in the United States have asthma, but vary in the degree of asthma control they experience and their response to therapy. Treatment typically includes a short-acting beta-agonist to relax muscles squeezing the patient's airways, in combination with longer-acting corticosteroids to reduce airway inflammation. However, 10-25 percent of patients with asthma do not respond to steroid treatment, and 1.8 million asthma patients required treatment in emergency departments during 2005.

Previous studies had looked at cytokine levels in lung fluid. However, these researchers looked at whether cytokine levels in the blood could help predict a patient's response to treatment and the degree to which the disease interferes with doing everyday activities. The researchers found that interleukin-3 and interleukin-18 levels were significantly higher in poorly controlled (PC) than well-controlled (WC) asthma patients. The same pattern was observed for 3 serum growth factors (fibroblast growth factor, hepatocyte growth factor, and stem-cell growth factor beta). Most (13 of 18) cytokine levels measured, as well as 5 of 6 serum growth factor levels measured, from PC and WC patients were significantly higher than those from nonasthmatic control patients.

The findings were based on analysis of subgroups of patients from an ongoing prospective study of inner-city adults with asthma. The researchers used the Asthma Control Questionnaire and Asthma Quality of Life Questionnaire, as well as a multiplex assay for detecting blood levels of 29 cytokines, 12 chemokines, 6 growth factors, and 3 adhesion molecules to compare the three groups. The study was funded in part by the Agency for Healthcare Research and Quality (HS13312).

More details are in "Detection of immunological biomarkers correlated with asthma control and quality of life measurements in sera from chronic asthma patients," by Sangita P. Patil, Ph.D., Juan P. Wisnivesky, M.D., Dr.P.H., Paula J. Busse, M.D., and others in the March 2011 Annals of Allergy, Asthma & Immunology 106(3), pp. 205-213.